i'll admit it was a huge factor but not the main reason, tge north and the south just hated each other for many reasons including pro/anti slavery
some schools teach/suggest this, but the reality is it was entirely over slavery. the other issues werent severe enough to push the southerners anywhere close to outright secession. slavery to them was a way of life, while all the other issues were economic/political, and we all know how modern americans are if they feel their way of life is under threat.
the difference is back then *everyone* in the south had the same perspective, so their “protest” turned into “forget you north, you cant boss us around”. the historical record very clearly points to slavery being the core issue, not the rest of the political stuff - if it was the rest of the stuff that was the more significant part of why they seceded, they would have done so long before lincoln became president.